I need a help to make sure the Energyplus code is correct. Based on one experiment for daylight harvesting Energyplus results are different from what obtained by EN 15193 and DIALux.

[abbasinejad]

Hi,
I had an simulation for a cubic room located in Auckland (New Zealand) each of room walls directed to the north, east, south, and west directions. The length and width of the room are both 5 meters. The north wall is totally covered by a window. I examined different heights of the room of 2.4 meters and 5.1 meters. The luminaires in the room can be dimmed for daylight harvesting and room type is office which only is used for business hours ( say 7 AM to 6 PM). The annual energy usage for lighting calculated by EN 15193 method and based on DIALux software outputs, show twice energy usage when height is 5.1 meters in comparison with 2.7 meters. But in Energyplus there is not substantial change. Interestingly, consumed energy decreases when height changes from 2.7 m to 5.1 m. It is a big question for me what is the source of this discrepancy? Is it some thing different from prevalent methods in Energyplus code? Thank you for your helpful comments.